Primer on Probiotics

April 1st, 2009

By Nora Simmons

Probiotic, prebiotic; good bugs, bad bugs. Every time we turn around, another study champions the benefits of these gut-friendly supplements. But what are they? What do they do? Why should we take them? We asked Angelica S. Vrablic, PhD, a leading expert in nutrition research and a probiotic guru, to give us the lowdown. Here’s what we learned:

1. Probiotics are non-pathogenic (not capable of causing harm) bacteria that naturally live in our gut.

3. The body doesn’t make probiotics on its own; we have to supply them, either by eating fermented food or taking supplements. Back in the good ol’ days, when Grandma pickled her garden-grown cucumbers, fermented the cabbage patch into sauerkraut, and cultured her own yogurt, our diets supplied all the healthy flora we needed. But now almost all fermented foods (even those found in natural grocery stores) contain added sugars and have undergone pasteurization, which kills the good bacteria along with the bad. “If you can find unpasteurized fermented foods (kimchi, pickles, and sauerkraut), buy pasteurized yogurt to which the probiotics have been added back, and eat plenty of prebiotics, you don’t need to supplement,” says Vrablic. But if you’re like most of us—and be honest—you need to supplement.

4. And you should. Every day. Especially after you’ve taken antibiotics. “Antibiotics kill bacteria, and because probiotics are bacterial cultures, they can’t survive. Your gut will desperately need to recolonize its healthy flora,” says Vrablic. “But wait until you finish your antibiotics before starting your probiotic supplements.” As long as you’re not on antibiotics currently, you can take probiotics at any time of the day, with or without food. And they’re totally safe; even a first-time probiotic user can confidently take the recommended dose every day.

5. So what is a prebiotic? Simply put, a prebiotic is food—a complex carb (fiber)—for your probiotic bacteria. For example, Lactobacillus acidophilus feed on the lactose from milk; they then produce lactic acid and thus yogurt. Common prebiotics include inulin (carb from chicory), pectin fiber (from citrus fruit), and almonds. Many probiotic supplements will contain a prebiotic formula too.

6. You can find formulas that specifically target different digestive issues: Lactobacillus acidophilus for gassy stomachs and lactose intolerance; bifidobacteria for intestinal problems and deeper digestive issues; or Lactobacillus rhamnosus for general gut and immune support. But Vrablic recommends finding a good all-around daily supplement that includes several strains so that you cover all your bases.

7. When you choose a supplement, remember: Any probiotic you take should contain at least 1 billion to 5 billion colony-forming units (CFUs). Probiotics come in liquid form (most concentrated), capsules, or chewable wafers (popular with kids). Many need to be refrigerated, but you can also find freeze-dried varieties that are stable at room temperatu